The invention relates to phosphinylmethyl or phosphorylmethyl succinic and glutaric acid analogs designed to inhibit xcex2-secretase in the metabolic processing of the amyloid precursor protein (APP). The invention also provides methods for the synthesis of phosphinylmethyl or phosphorylmethyl succinic and glutaric acid analogs, and further provides therapeutic methods for administration of the compounds for the treatment of plaque formation, especially in Alzheimer""s disease.
Alzheimer""s disease (AD) affects approximately 5-15% of the U.S. population over age 65. This disease is frequently associated with individuals over the age of 60. Alzheimer""s disease is the most frequent cause of institutionalization for long-term care. It is now estimated that 4.1 million Americans suffer from AD incurring $100 billion in U.S. health care costs per year.
Alzheimer""s disease is characterized by the deposition of xcex2-amyloid (Axcex2) peptide in the extracellular compartment of the brain in the form of cognophilic amyloid angiopathy and amyloid plaques. (Small, D. H., Mclean, C. A, Alzheimer""s disease and the amyloid xcex2 protein: what is the role of amyloid?, 73 J. Neurochem 443-49, 1999; Masliah, E., Role of amyloid precursor protein in the mechanisms of Neurodegeneration in Alzheimer""s disease, 77 Lab. Investig. 197-209, 1997). Recent research on cellular and molecular aspects of Alzheimer""s disease over the last two decades suggested that the metabolic fate of the amyloid precursor protein (APP) is one of the key factors in the pathogenesis of AD. (Lins, L., et al., Molecular determinants of the interaction between the C-terminal domain of Alzheimer""s xcex2-amyloid peptide and apolipoprotein E xcex1-Helices, 73 J. Neurochem. 758-69, 1999; Selkoe, D. J., Normal and abnormal biology of the xcex2-amyloid precursor protein, 17 Annu. Rev. Neurosci., 489-517, 1994; Tanzi, R. E., et al., The gene defects responsible for familial Alzheimer""s disease, 3 Neurobiology of Disease 159-68, 1996; Selkoe, D. J., Alzheimer""s disease: genotypes, phenotype and treatments, 275 Science 630-31, 1997; Hardy, J. Amyloid, the presenilins and Alzheimer""s disease, 20 TINS 154-159, 1997; Lendon, C. L., et al., Exploring the etiology of Alzheimer disease using molecular genetics, 277 JAMA 825-31, 1997).
Amyloid precursor protein is a 695-770 amino acid membrane spanning glycoprotein, widely and constitutively expressed in the neurons and glial cells in peripheral tissues. Axcex2, a 39-42 amino acid peptide, constitutes part of the ectodomain of APP and extends partly to the transmembrane domain. There are three secretory pathways involved in the APP processing. xcex1-Secretase cleaves Lys16 and Leu17 of Axcex2 sequence giving rise to soluble APP (sAPP) (see FIG. 1). (Small, D. H., Mclean, C. A., Alzheimer""s disease and the amyloid xcex2 protein: what is the role of amyloid?, 73 J. Neurochem 443-49, 1999; Masliah, E., Role of amyloid precursor protein in the mechanisms of Neurodegeneration in Alzheimer""s disease, 77 Lab. Investig. 197-209, 1997). This pathway is non-amyloidogenic and to date, the products P3 and C83 are considered non-participants in AD pathology. Cleavage of APP by xcex1-secretase produces a large soluble NH2-terminal fragment, sAPPxcex1, and a 10-KD membrane-bound COOH terminal fragment C83. C83 can be further cleaved by one or more xcex3-secretases to release the nonpathogenic p3 peptide. (Skovronsky, D. M., et al., Protein kinase C-dependent xcex1-secretase competes with xcex2-secretase for cleavge of amyloid-xcex2 precursor protein in the trans-Golgi network, 274(4) J. Biol. Chem. 2568 -75, 2000; Jolly-Tornetta, C., Wolf, B. A., Regulation of amyloid protein (APP) secretion by protein kinase Cxcex1 in human Ntera 2 neurons (NT2N), 39 Biochemistry 7428-35, 2000).
Through the xcex2-secretory pathway, Axcex2 is produced from the cleavage of APP at the N terminus of Axcex2 by xcex2-secretase and cleavage at the C terminus of Axcex2 by xcex3-secretase. The extended forms of Axcex2 aggregate more readily and may seed amyloid fibril polymerization during the early stages of plaque formation. The Axcex2 accumulation is critical to AD as suggested by findings that mutations in several genes associated with familial AD (FAD) increase amyloidogenic Axcex2 production. (Selkoe, D. J., Alzheimer""s disease: genotypes, phenotype, and treatments, 275 Science 630-31, 1997; Price, D. L., Sisodia, S. S., Mutant genes in familial Alzheimer""s disease and transgenic models, 21 Annu. Rev. Neurosci. 479-505, 1998).
A growing list of evidence has demonstrated that enhanced sAPP secretion is associated with diminished Axcex2 production, suggesting that the secretory processing of APP to sAPPxcex1 reduces the formation of potentially amyloidogenic derivatives. Most of the experimental evidence suggests that xcex1 and xcex2 secretases compete for the same pool of APP. (Skovronsky, D. M., et al., Protein kinase C-dependent xcex1-secretase competes with xcex2-secretase for cleavage of amyloid-xcex2 precursor protein in the trans-Golgi network, 275(4) J. Biol. Chem. 2568-75, 2000; Jolly-Tornetta, C., Wolf, B. A., Regulation of amyloid protein (APP) secretion by protein kinase Cxcex1 in human Ntera 2 neurons (NT2N), 39 Biochemistry 7428-35, 2000). Therefore, the relative ratio of amyloidogenic vs. non-amyloidogenic products could be altered by regulating the activity of either secretase.
Additionally, presenilin 1 was also identified recently to control the hydrolysis at the intramembrane xcex3-secretase site and has been postulated to be itself the responsible protease. (Wolfe, M. S. et al., Are presenilins intramembrane-cleaving proteases? Implication for the molecular mechanism of Alzheimer""s Disease, 38 Biochemistry 11223-30, 1999; Selkoe, D. J., Wolfe, M. S., In search of xcex3-secretase; Presenilin at the cutting edge, 97 Proc. Natl. Acad. Sci. 5690-92, 2000; Li, Y-M. et al., Presenilin 1 is linked with xcex3-secretase activity in the detergent solubilized state, 97 Proc. Natl. Acad. Sci. 6138-43, 2000; De Strooper, B. et al., Deficiency of presenilin-1 inhibits the normal cleavage of amyloid precursor protein, 391 Nature 387-90, 1998; Wolfe, M. S. et al., Two transmembrane aspartates in presenilin-1 required for presenilin endoproteolysis and xcex3-secretase activity, 398 Nature 513-17, 1999; De Strooper, B. et al., A presenilin-1-dependent xcex3-secretase-like protease mediates release of Notch intracellular domain, 398 Nature 518-22, 1999; Kimberly, W. T. et al., The transmembrane aspartates in presenilin 1 and 2 are obligatory for xcex3-secretase activity and amyloid xcex3-protein generation, 275 J. Biol. Chem. 3173-78, 2000). Although several xcex3-secretase inhibitors have been reported, (Rishton, G. M. et al., Fenchylamine sulfonamide inhibitors of amyloid xcex2 peptide production by the xcex3-secretase proteolytic pathway: Potential small-molecule therapeutic agents for the treatment of Alzheimer""s disease, 43 J. Med. Chem. 2297-99, 2000; Seiffert, D. et al., Presenilin-1 and 2 are molecular targets for xcex3-secretase inhibitors, J. Biol. Chem. (in press); Li, Y.-M. et al., Photoactivated xcex3-secretase inhibitors directed to the active site covalently label presenilin 1, 405 Nature 689-94, 2000; Wolfe, M. S. et al., Peptidomimetic probes and molecular modeling suggest that Alzheimer""s xcex3-secretase is an intramembrane-cleaving aspartyl protease, 38 Biochem. 4720-27, 1999; Wolfe, M. S. et al., A substrate-based difluoro ketone selectively inhibits Alzheimer""s xcex3-secretase activity, 41 J. Med Chem. 6-9, 1998) the processing of APP by xcex2-secretase is thought to be the rate-determining step in Axcex2 production. Therefore, xcex2-secretase inhibitor emerges as a preferred therapeutic target in the treatment of Alzheimer""s disease.
More recently, significant efforts have been devoted towards the identification of the xcex2 protease (Selkoe, D. J., Translating cell biology into therapeutic advances in Alzheimer""s disease, 399 Nature 23-31, 1999; Vassar, R., et al., xcex2-Secreatase cleavage of Alzheimer""s amyloid precursor protein by the transmembrane aspartic protease BACE, 286 Science 735-41, 1999; Hussain, I., et al., Identification of a novel aspartic protease (Asp2) as xcex2-secretase, 14 Mole. Cell. Neurosci. 419-27, 1999; Yan, R., et al., Membrane-anchored aspartyl protease with Alzheimer""s disease xcex2-secretase activity, 402 Nature 533-37, 1999; Sinha, S., et al., Purification and cloning of amyloid precursor protein xcex2-secretase from human brain, 402 Nature 537-40, 1999; Lin, X., et al., Human aspartic protease memapsin 2 cleaves the xcex2-secretase site of xcex2-amyloid precursor protein, 97 Proc. Natl. Acad. Sci. 1456-60, 2000) so design and synthesis of xcex2-secretases inhibitors become possible. A JACS communication appeared as the first report on the peptidyl xcex2-secretase inhibitor. (Ghosh, A. K. et al., Design of potent inhibitors for human brain memapsin 2 (xcex2-secretase), 122 J. Am. Chem. Soc. 3522-23, 2000).
Nevertheless, the peptidyl compounds exhibit problems with instability, low bioavailability, and poor pharmacological profiles. There is a need in the field of the invention for pseudo- and/or non-peptidyl potent and selective inhibitors that represent promising features of xcex2-secretase inhibitors. The invention fulfills these needs and more, as will become apparent to one of skill in the art upon reading the following disclosure.
The invention provides a compound of formula (I): 
or salts or hydrates thereof;
wherein n is 1 or 2;
wherein X is a phosphinylmethyl or phosphorylmethyl derivative of the formula (II): 
wherein R1 is H, OH, R, OR, SR, NR2, (CH2)mC(O)R, (CH2)mCOOR, (CH2)mP(O)(OR)2, (CH2) mS(O)R, or (CH2)mSO2R; wherein each R is independently H, (C1-C22)alkyl, (C6-C10)aryl, (C3-C8)cycloalkyl, (C2-C22)alkenyl, (C5-C8)cycloalkenyl, (C7-C32)aralkyl, (C7-C32)alkylaryl, (C9-C32)aralkenyl, or (C9-C32)alkenylaryl; and where m is 1 to 5;
wherein R2 is H, R, OR, SR, NR2, (CH2)mC(O)R, (CH2)mCOOR, (CH2)mP(O)(OR)2, (CH2) mS(O)R, or (CH2)mSO2R with the proviso that R2 is not OH;
wherein each R is independently H, (C1-C22)alkyl, (C6-C10)aryl, (C3-C8)cycloalkyl, (C2-C22)alkenyl, (C5-C8)cycloalkenyl, (C7-C32)aralkyl, (C7-C32)alkylaryl, (C9-C32)aralkenyl, (C9-C32)alkenylaryl, a dipeptide; a tripeptide; a heterocycle, or a derivative of said heterocycles,
where m is 1 to 5.
In one aspect, the invention provides pseudo- and/or non-peptidyl agents as xcex2-secretase inhibitors. These inhibitors decrease the xcex2-amyloid available for plaque formation.
The invention additionally provides agents for the treatment of various diseases associated with xcex2-amyloid plaques, especially but not limited to the treatment of neurological diseases, for example, Alzheimer""s disease.
The invention further provides libraries of phosphinylmethyl (R1 is a C-linked substituent as defined above) and/or phosphorylmethyl (R1 is OR) succinic acid derivatives (n=1) in which the succinoyl moiety is constant while various substitutents as given above are permitted at position R2. Thus, in one embodiment, a phosphorylmethyl succinoyl core is attached to a plurality of R2 groups, producing a class of compounds herein termed LQ-xcex21 and LQ-xcex22 series. Similarly, a phosphinylmethyl succinoyl core produces a library herein termed LQ-xcex23 series including LQ-xcex24 and LQ-xcex25 derivatives.
The invention further provides libraries of phosphinylmethyl (R1 is a C-linked substituent as defined above) and/or phosphorylmethyl (R1 is OR) glutaric acid derivatives (n=2) in which the moiety is constant while various substitutents as given above are permitted at position R2. Thus, in one embodiment, a phosphorylmethyl core is attached to a plurality of R2 groups, producing a class of compounds herein termed LQ-xcex21 and LQ-xcex22 series. Similarly, a phosphinylmethyl core produces a library herein termed LQ-xcex23 series including LQ-xcex24 and LQ-xcex25 derivatives.
The invention further provides compositions comprising phosphinylmethyl and/or phosphorylmethyl succinic and glutaric acid derivatives, or their salts, or their hydrates in a pharmaceutically acceptable carrier. In further embodiments, methods are provided for treatment of a subject having an over expression of xcex2-amyloid (for example a subject with Alzheimer""s disease-like symptoms), in which an effective amount of the aforementioned composition is administered to the subject.
The invention in another aspect provides methods for preventing or reducing the progress of plaque formation in which the cell is contacted with an effective amount of the aforementioned phosphinylmethyl and/or phosphorylmethyl succinic and glutaric acid derivatives. This will prove especially useful in diseases such as Alzheimer""s disease.
In still a further aspect, the invention provides a method for inhibiting xcex2-secretase, in which the protease is contacted with an effective amount of the aforementioned phosphinylmethyl and/or phosphorylmethyl succinic and glutaric acid derivatives. The instant invention provides numerous advantages over known compounds, such as lack of peptide characters and easy scale-up. In particular, the LQ-xcex2series compounds are superior to previously published peptidyl xcex2-secretase inhibitor in that either phosphinyl or phosphoryl moiety preclude the chirality problem, which makes it easier for synthesis. These and other advantages will become apparent to those of skill in the art upon reading the following detailed description.
In another aspect, the invention the invention provides pseudo- and/or non-peptidyl agents for increasing the xcex1-secretase pathway activity.